Phase Composition and Hardening of Castable Al – Ca – Ni – Sc Alloys Containing 0.3% Sc

Abstract

The phase composition of aluminum alloys of the Al – Ca – Ni – Sc system containing 0.3 wt.% Sc is studied. It is shown that the aluminum solid solution may be in equilibrium not only with binary phases (Al₄Ca, Al₃Sc and Al₃Ni) but also with a ternary Al₉NiCa compound. The temperature of attainment of maximum hardening due to precipitation of nanoparticles of phase Al₃Sc is determined for all the alloys studied. Principal possibility of creation of castable alloys based on an (Al) + Al₄Ca + Al₉NiCa eutectic, the hardening heat treatment of which does not require quenching, is substantiated.